Gas-operated gun



Dec. 14, 1937. s. H. M GREGOR GAS OPERATED GUN Filed April 22, 1956 \Nmm mm mm KN MN Patented Dec. 14, 1937 UNITED STATES PATENT orrlce 3Claims.

'(Granted under the Act of March 3, 1883, as amended April 30, 1928; 370G. 757) The invention described herein may be manufactured and used byor for the Government for governmental purposes, without the payment tome of any royalty thereon.

This invention relates to and is an improvement on gas-operated guns.

In guns of the gas-operated type, a piston movable by the gases ofdischarge is directly connected to an operating rod or actuator which byits movement unlocks the breech bolt. The sudden blow imparted to thistype of rod or actuator may result in damage and breakage of the rod oractuator and of the bolt locking mechanism. Furthermore, at the momentof unlocking and opening of the breech the pressure therein is high.

Extraction of the cartridge case under high pressure may be difiicult,resulting inruptured cartridge cases or torn extracting grooves.

The purpose of this invention is to provide a delay action without lossof actuating power, and to apply the necessary power smoothly withoutviolent or sudden contact of moving parts.

To these and other ends, the invention consists in the construction,arrangement andcombination of elements described hereinafter and pointedout in the claims forming a part of this specification.

A practical embodiment of the invention is illustrated in theaccompanying drawing, wherein:

Fig. 1 is a view in side elevation of a gun.

Fig. 2 is an enlarged view partly in side elevation and partly insection and showing the parts in the normal action closed position.

Fig. 3 is a similar view showing the parts at 5 the start of the closingmovement of the bolt from the full open position.

Fig. 4 is a transverse sectional view taken generally on the line 4--4of Fig. 2 and showing the breech bolt in locked position.

Fig. 5 is a plan view of the front part of the breech bolt.

Fig. 6 is an enlarged view in side elevation of the handle piece of thebreech-operating rod.

Fig. 7 is a sectional view on the line 11 of Fig. 6.

Referring to the drawing by characters of reference there is shown a gunbarrel 5 threaded or otherwise secured in the front end of a receiverframe 6. A breech bolt reciprocally mounted in the receiver is formedwith laterally extending wings, the left wing 8 having a pair of lugs 99adapted, in breech-locking position, to enter recesses Ill-40 in thereceiver and the right wing H, adapted, in breech-locking position, toenter 55 a slot l2 in the receiver, and having a cam memher l3projecting beyond the side of the receiver. The bolt is unlocked by arotary motion, and during reciprocation the lugs 9-4! ride a guide wayl4 while the right wing ll rides over the upper edge of thecorresponding side of the receiver. 5?

A cylinder l5 carried by the barrel 5 underneath its front part receivesa portion of the gases of discharge through a port i 6 at the muzzle ofthe barrel. A hollow piston I! working in the cylinder has an open rearend for receiving the front 1 part of a hollow rod I 8 which in thenormal position of rest of these elements has its front extremityspaced. a slight distance from a. plug 19 closing the front end of thepiston. A helical spring 20 is confined between the plug 19 and a Thepiston llhas a collar 25 on its rear end for 20 engaging the rear edgeof the cylinder l5 and limiting forward movement of the piston. Thecollar 25 is also arranged to engage a collar 25 on the rod. l8- whenthe piston moves rearwardly and takes-up'the distance between its plugl9 and the 25 front end of the rod l8. The rod I8 is held in place by alatch 21 during the initial and independent rearward movement of thepiston. The latch is carried by a stationary element, such as the stock28, and is held by a. spring 29 with its 30 end 30 normally in positionto engage a lug 3! on the rod [8. The engagement between the latch end30 and lug 3| is of a readily releasable type capable of being releasedwhen sufiicient force is applied to the rod l8 during manual retractingthereof.

An ofiset finger 32 on the rear end of the piston is arranged to tripthe latch 21 when the collar 25 of the piston picks up the collar 26 ofthe rod. The rear end of the finger is provided with a lug 33 adapted toengage the rear face of the collar 26. This provision is made so thatwhen retraction is to be accomplished by manually acting on the rod l 8the piston will be carried along, (Fig. 2) and also for the purpose oflimiting the independent counterrecoil movement of the piston under theinfluence of its spring 29.

An offset handle piece 34 on the rear end of the rod I8 is disposedalongside the receiver and has a stud 35 riding in a guide groove 36 inthe receiver. The handle piece is formed with a. recess 3! having afront cam surface 38 and a rear cam surface 39. The projecting cammember E3 on the right wing of the breech bolt is disposed in the recess31. When the rod I8 is moved rearwardly,

rod I8 under influence of its spring23.

The handle piece 34 is provided with a handle 48 whereby the rod I8 ismanually retracted to initially load a cartridge into the'chamber of thegun barrel.

piston I'I move together by virtue'of the coupling between the lug 33 onthe finger 32 of the'piston During this operation the rod I8 and and thecollar 26 on the rod I8. The force applied to manually retract the rod,I8 causes the latch 2'! to be disengaged from the lug 3I.

When the gun is fired, a portion of the gases of discharge enters thecylinder I 5 and drives the piston I I rearwardly. Since therod I8 isheld by the latch 21, the initial and independent movement of the pistoncompresses the spring 20. When the piston has moved about three quartersof an inch it disengages the latch 21 from the rod I8 and picks up therod, which is driven rearwardly. The, initial movement of the rod I8unlocks the bolt '1, after which it is'moVed-to the rear so that it mayperform its usual functions as well understood in the art; The spring 23which is energized during retraction'of the rod restores the parts intobattery, the cam member I3 of the bolt limiting forward movement of therod I8 while the piston continues forward under the influence of itsspring. I

The piston takes the initial blow and insures a smooth movement of therod I8 so that the parts will not be damaged or broken during theunlocking of the bolt I.

I claim:

receiver, a breech bolt reciprocable in the receiver, means whereby thebolt is locked to the With the bolt locked, the cam member I3 limitsforward movement of the receiver", a cylinder fixed to the barrel, a gaspas"- sage between the barrel and cylinder, a piston in the cylinder, acollar on the rear end of the piston and engageable with the cylinder tolimit forward movement of the piston, an offset finger extendingrearwardlyrfrom the piston, a bolt-0perating rod having its front partslidable within the piston and adapted to be engaged and movedrearwardly by the piston, a spring seat in the rod, a driving spring forthe rod, a spring between the spring seat of the rod and the front endof the pistoma collar fixed on the rod and movable between the end ofthe piston and the end of the finger 'of the piston, a latch releasablyengaging .the rod.to hold it against rearward movement,

receiver, a breech bolt reciprocable in the receiver, means whereby thebolt is locked to the receiver, a cylinder fixed, to the barrel, a gaspassage between the barrel and cylinder, a piston in the cylinder, abolt-operating rod having its front part slidable within the piston,said piston and rod having a'small relative movement before the pistonengages the rod to move it rearwardly, a spring seated on the rod andacting on the piston to hold it in advance of the rod, a driving springfor the rod, a latch releasably engaging the rod to hold it againstrearward movement; and means whereby the piston controls the latch.

3. in a gun, a receiver, a barrel fixed to the receiver, a breech boltreciprocable in the receiver, means whereby thebolt is locked tothe'receiver, a cylinder fixed to the barrel, a gas passage between thebarrel and cylinder, a piston in the cylinder, a bolt-operating rodhaving its front part slidable within the piston, said piston and rodhaving a small relative movement before the piston engages the rod tomove it rearwardly, a spring seated on the rod and acting on the pistonto hold it in advance of the rod, and a driving spring for the rod.

' STEPHEN H. MACGREGOR.

